1. Field of the Invention The present invention relates to a particle reducing method and a film deposition method.
2. Description of the Related Art
A film deposition method in which a thin film is formed on a semiconductor wafer (hereinafter, referred to as a “wafer”) is known as one of methods of manufacturing a semiconductor integrated circuit. A film deposition apparatus which is used for the film deposition method includes a sealable chamber, a susceptor provided in the chamber on which a wafer is to be mounted, a source gas supplying unit which supplies a source gas onto the wafer mounted on the susceptor, and an evacuation device which is connected to the chamber and evacuates the source gas.
When forming a thin film on a wafer using such a film deposition apparatus, there is a problem that a deposited object is also formed inside the chamber to cause particles when the deposited object is peeled. In order to solve this problem, a method of removing the deposited object inside the chamber has been examined (see Patent Document 1, for example).
Here, in accordance with the miniaturization of the circuit components formed on the wafer, it is required to further improve the film thickness uniformity and controllability of the film thickness of the thin film. In order to respond to such a requirement, a film deposition method so-called “Atomic Layer Deposition” (ALD) or “Molecular Layer Deposition” (MLD) is expected.
For this film deposition method, a film deposition apparatus as follows may be used. The film deposition apparatus includes a susceptor, on which plural wafers are to be mounted, rotatably provided in a vacuum chamber and, a first reaction gas supplying unit which is capable of supplying a first reaction gas onto the plural wafers which are mounted on the susceptor, and a second reaction gas supplying unit which is provided apart from the first reaction gas supplying unit in a rotational direction of the susceptor and is capable of supplying a second reaction gas which can react with the first reaction gas. With this film deposition apparatus, when the first reaction gas and the second reaction gas are respectively supplied from the first reaction gas supplying unit and the second reaction gas supplying unit while rotating the susceptor, the first reaction gas and the second reaction gas are alternately adsorbed onto the surfaces of the wafers on the susceptor so that thin films, which are a result of the surface reaction, are formed on the wafers, respectively.
Specifically, in an ALD apparatus provided by the inventors of the present invention (see Patent Document 2), the first reaction gas and the second reaction gas can be sufficiently separated from each other so that the deposited object (residue) is hardly deposited inside the vacuum chamber. Therefore, generation of the particles due to the deposited object deposited inside the vacuum chamber can be sufficiently lowered.
However, recently, the requirement to reduce the particles has been increased so that a method of further reducing the particles is required.
[Patent Document]
    [Patent Document 1] Japanese Laid-open Patent Publication No. 2008-159787    [Patent Document 2] Japanese Patent No. 4661990